標題: Polyfluorene presenting dipolar pendent groups and its application to electroluminescent devices
作者: Chien, Chen-Han
Shih, Ping-I
Wu, Fang-Iy
Shu, Ching-Fong
Chi, Yun
應用化學系
Department of Applied Chemistry
關鍵字: atomic force microscopy (AFM);charge transport;conjugated polymers;electrochemistry;light-emitting diodes (LED)
公開日期: 1-六月-2007
摘要: We have synthesized a blue-light-emitting polyfluorene derivative (PF-TPAOXD) that presents sterically hindered, dipolar pendent groups functionalized at the C-9 positions of alternating fluorene units. The incorporation of the dipolar side chains, each comprising an electron-rich triphenylamine group and an electron-deficient oxadiazole group connected through a pi-conjugated bridge, endows the resultant polymer with higher highest occupied molecular orbital and lower lowest unoccupied molecular orbital energy levels, which, consequently, lead to an increase in both hole and electron affinities. An electroluminescent device incorporating this polymer as the emitting layer exhibited a stable blue emission with a maximum brightness of 2080 cd/ m(2) at 12 V and a maximum external quantum efficiency of 1.4% at a brightness of 137 cd/m(2). Furthermore, atomic force microscopy measurements indicated that the dipolar nature of PF-TPAOXD, in contrast to the general nonpolarity of polydialkylfluorenes, provided a stabilizing environment allowing the polar organometallic triplet dopant to be dispersed homogeneously. We also fabricated an electrophosphorescent device incorporating PF-TPAOXD as the host material doped with a red-emitting osmium complex to realize red electroluminescence with Commission Internationale de l'Eclairage color coordinates of (0.66, 0.34). The resulting device exhibited a maximum external quantum efficiency of 7.3% at a brightness of 1747 cd/m(2) and a maximum brightness of 7244 cd/ m(2). (C) 2007 Wiley Periodicals, Inc.
URI: http://dx.doi.org/10.1002/pola.21971
http://hdl.handle.net/11536/10726
ISSN: 0887-624X
DOI: 10.1002/pola.21971
期刊: JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
Volume: 45
Issue: 11
起始頁: 2073
結束頁: 2084
顯示於類別:期刊論文


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